code: def run(self):
      # prints the progress from the child work
      print(round(self.child_work.progress, 4))
      self.child_work.run()
      if self.child_work.counter == 1.0:
          print("1 hour later!")
  
file_path: pytorch-lightning/docs/source-app/code_samples/quickstart/app_03.py
imports: from time import sleep
  from lightning.app import LightningWork, LightningFlow, LightningApp
label_desc: Use image node_id 2 for calling the RootFlow obj's underlying member method code with example usage: obj.run() without return types